Commercially available omega-carboxy-aldehydes and glycine have been subjected to the catalytic action of an L-threonine aldolase from Escherichia coli to give the corresponding beta-hydroxy-alpha-(L)-amino acids as a mixture of erythro/threo epimers. Specifically, the reaction with glyoxylic acid (2) gave the epimeric beta-hydroxy-(L)-aspartates (t,e)-9 that could be isolated by ion-exchange chromatography in 67% yield. Following esterification and N-Boc protection, the two epimers could be isolated as pure compounds. Similarly, the aldolase-catalyzed addition of glycine to succinic semialdehyde (4) gave the expected mixture of beta-hydroxy-L-alpha-aminoadipic acids (t)-12 and (e)-12 in 34% yield. (C) 2008 Elsevier Ltd. All rights reserved.